engine builders ??

[Broncobowsher]

The good blocks were manufactured with C9-D4 casting numbers, '69-74 model years.

I go against that...
The '69 and '70 have a shorter deck height which is an old hot rodders trick for more compression. But the replacment parts are mostly based on the newer engine with the .023" taller deck. I feel that short deck is more of a liability then a benifit.

The post ~83 blocks are one piece rear main seal. and the F4 blocks are roller compatible (factory roller cam lifter bores for use with a roller cam).

Any of the 351W blocks will live with up to 700~750 HP. So going for a stronger block isn't needed, but getting a better block is a good idea. By better I mean things like newer and less wear, better sealing (rear main 1-piece), and roller cams are nice.

 

[360 4V]

I don't know about the NP 3550 but I would I have never before turned down cubic inches. Just be considerate with that transmission and you should be fine. You will love having big block displacement in that little Bronco!

 

[360 4V]

Broncobowsher, thanks for the help. If all 351W blocks will hold 750 hp, will an older high nickel block hold up better to a turbocharged 408 stroker making more than 750 hp?

 

[buckintone]

Get a 351 roller motor, and what the hay do.u need 750 hp on a Bronco for? Fast as Hell O to 60 is cool, anything over that may be in barrel roll form. I have a 94 roller 408 with the stock 94 cam, afr 185s, roller rocks, performer efi, 42 lb injectors, 70mm Accufab, 90mm maf, long tubes and a 9 psi centrifugal super charger. I'm expecting about 600 hp, and I'm an idiot! ;D

 

[360 4V]

Hot d#$n! I was thinking about 408W with four turbochargers. Are two turbochargers better than one?

 

[buckintone]

Lol! I like u dude, u crack me up crazy man, I'd love to see a 750+ bronco!

 

[360 4V]

http://s1082.photobucket.com/albums/j365/360FE/#!cpZZ2QQtppZZ16

 

[Edger6]

I got my bronco with a 302, I thought I was going to be happy, and I am because I have a good running 302 for sale. I just pick up my 351 its not a roller but its not nessacary in my mide, but hey if u want I know a junk yard that has a 351m400 sitting in a 78 full size bronco. Im going to build my 351.

 

[broncnaz]

Its my understanding that there are no high nickle 351 blocks at least not american blocks early blocks are considered stronger only due to larger main webbing. the mexican blocks do have higher nickle and probably the older style main webbing as well. the higher nickle content actually helps more in the area of wear. The roller blocks are supposedly the weakest blocks out of all of them. but really unless your racing and actually pumping 700+ HP and really beating the engine I wouldnt worry much about it. Just get whatever 351 block you can get. of course if your building a 408 stroker and gong turbo then your really better off with a aftermarket block.
I'll roast you 3604V as I dont see any dyno sheets in those pics much less a bronco with a engine in it.%)

 

[buckintone]

Its my understanding that there are no high nickle 351 blocks at least not american blocks early blocks are considered stronger only due to larger main webbing. the mexican blocks do have higher nickle and probably the older style main webbing as well. the higher nickle content actually helps more in the area of wear. The roller blocks are supposedly the weakest blocks out of all of them. but really unless your racing and actually pumping 700+ HP and really beating the engine I wouldnt worry much about it. Just get whatever 351 block you can get. of course if your building a 408 stroker and gong turbo then your really better off with a aftermarket block.
I'll roast you 3604V as I dont see any dyno sheets in those pics much less a bronco with a engine in it.%)

Good info, but I contest after market block for a 408 comment. Its pretty well known that 408 is the cut off point for the stock block, it can handle anything u throw at it in 408 form. The above 408 strokers start to get dicey, anything over a 427 needs a dart.

 

[360 4V]

My 351W:
-'79 block .040" over
-'78 cylinder heads
1.94"/1.60" Chevy valves
chamber unshrouded for larger valves
chamebers sanded ~12 hours
lots of careful pocket porting and bowl work
port matched to the Felpro gasget in picture, I think it was #1262
I am going to build the ports up with JB weld and shape them.
-TRW forged pistons .040" over
-Schneider Racing Cams 262/270 hydraulic flat tappet, I am getting it exchanged for the equivalent with a 114 LSA.
-estimated 300 hp and 400 torque.

I never said I had several hundred horspower and turbo chargers. I was just trying to make an example of how far we can push the 351W block. I am going to get a stroker crank later and dream of someday putting a turbocharger or multiple turbochargers on.

 

[broncnaz]

Good info, but I contest after market block for a 408 comment. Its pretty well known that 408 is the cut off point for the stock block, it can handle anything u throw at it in 408 form. The above 408 strokers start to get dicey, anything over a 427 needs a dart.

I was refering to a 408 with a turbo. Since it was mentioned in passing. Most 408's especailly the ones we tend to build and use in broncos are not a issue. Most wont see over 500 hp anyhow.

 

[buckintone]

I was refering to a 408 with a turbo. Since it was mentioned in passing. Most 408's especailly the ones we tend to build and use in broncos are not a issue. Most wont see over 500 hp anyhow.

I have a supercharged 408, 9lbs boost and I'm expecting around 600 hp, the stock block should handle this easily right?

 

[broncnaz]

Dont see why not. Basically as long as your not hammering the engine a lot like as is done in racing it will be fine.
I've seen stock blocked twin turbo'd 302's that put out almost 1000 hp stay together. you just dont want to hammer them as they will come apart sooner or later.

 

[360 4V]

I am under the understanding that horsepower alone holds the rotating assembly together while rpms alone pull it apart. With that said I would rather have 500 hp at a low rpm on a blower engine rather than a naturally aspirted engine that makes 500 hp at 7,800 rpm.

I also read somewhere that cast iron is tougher toward compressing than steel but steel is much tougher when submitted to stretching.

 

[KyleQ]

It's funny how things spiral out of control-

Windsor blocks will handle over 650hp out of the box, 302's split at the 500 mark.

No point in stroking a 302 when a 351 fits

Get a roller 351W block, rebuild it right, put some nice aftermarket heads on it (TFS 185) and a big cam with a nice LSA and make 450/450 all day long - that is what I did.

 

[OX1]

I go against that...
The '69 and '70 have a shorter deck height which is an old hot rodders trick for more compression. But the replacment parts are mostly based on the newer engine with the .023" taller deck. I feel that short deck is more of a liability then a benifit.

The post ~83 blocks are one piece rear main seal. and the F4 blocks are roller compatible (factory roller cam lifter bores for use with a roller cam).

Any of the 351W blocks will live with up to 700~750 HP. So going for a stronger block isn't needed, but getting a better block is a good idea. By better I mean things like newer and less wear, better sealing (rear main 1-piece), and roller cams are nice.

Yeah, I recently ditched an entire 69, 351w I had been saving for 20 years just for the block. I came to the same conclusion about parts availability. You can get parts, but it's still limited, comapratively.

Plus, I don't see being able to use much more than 500 HP in any rig unless your purely racing, so what is the point of bothering with anything but a later model stock W block.

 

[KyleQ]

Yeah, I recently ditched an entire 69, 351w I had been saving for 20 years just for the block. I came to the same conclusion about parts availability. You can get parts, but it's still limited, comapratively.

Plus, I don't see being able to use much more than 500 HP in any rig unless your purely racing, so what is the point of bothering with anything but a later model stock W block.

I just did the same thing, ditched the 69' block I had, it would have been way too hard to get the compression down in the 427 I was building with it. Not worth the hassle-

Your next point was one I intended to make as well - hell, even 400HP is more than enough. Most members on here don't even break the 37" tire range, so what is the point to the gigantic HP numbers everyone goes after? Seriously - a bone stock 351W with EFI on it and a manual transmission is probably more than you will ever need.

Built motor make lots of power, but at the expense of heat, durability and sometimes expensive fuel. A bone stock motor will run at WOT all day long and not complain - they are made to run 150K+ miles on just regular oil changes and minor maintenance.

 

[360 4V]

What is a good guide line for not overrevving a 351W, 6,000 rpm max? I have read many threads where small blocks are coming apart up there. Some people get lucky and rev over 7,000 rpm for few bursts, others hold it at or above 6,500 rpm for too long and it comes apart. So with my limited authority I am nominating 6,000 rpm for 351Ws redline.

 

[KyleQ]

6k? Stop reading the drag racing boards and throw that number out of the window. We want torque, and we want it plentiful and at the low end of the spectrum. Most cams folks use here stop making power past 4-4500 RPM - all you are doing past that is making noise.

6K RPM isn't what I would call max either - maybe in stock form, but with the proper parts I don't see a problem with 7500RPM in bursts. Again - in an EB I would assume a torque style cam...

But if you are worried about driveline failure or missed shifts getting you into the stratosphere of the RPM spectrum, I would say 6K is a safe place to stop it, 5700 would be fine as well.